With the increasing requests of human intelligent life, the increasing requirements of developing intelligent products, and the growing of Internet of Things (IoT), the requirements of data transmission and processing are increasing day by day. In a centralized data processing center, servers are regarded as key elements and have motherboards including CPU, chipsets, memories, and equivalent digital chips for data processing with power supplies and necessary peripheral elements. For increasing the processing capacity of servers in a unit volume, the number of digital chips and the density of integration are increased correspondingly. Consequently, the ratio of occupied space and the power loss are increased. Therefore, the power supply (also called as motherboard power due to that the power supply and the digital chips are disposed on the same motherboard) employed by the system for providing power to the digital chips is expected to have higher efficiency, higher power density and smaller occupied space, so as to facilitate the entire server and even the entire data center to save energy and minimize the occupied area.
Generally, the power with the low voltage and the large current is provided to the digital chips mentioned above. For reducing the influences of power loss and impedance of the output wire, power supplies which are capable of providing power to the digital chips are directly disposed on the motherboard and located as close as possible to the digital chips. Therefore, the power supply which is capable of providing power to the digital chip directly is called as a point of the load (POL) power supply. The above-mentioned power supply has an input power provided from other power source. The typical POL power supply has an input voltage about 12 volts.
On the other hand, for achieving the applications in a distributed portable data processing terminals, the constituent elements and the digital chips have to be integrated into a small space and keep working for a long time. In addition, lower operating voltage is provided to the constituent elements and the digital chips. Generally, the lower operating voltage is provided by an energy storage device such as 3V to 5V battery. Therefore, the power supply tends to be requested with a high efficiency and a high power density.
At present, in a low-voltage DC/DC converter, a buck converter is usually employed to provide various output voltages ranged from 0 volt to 5 volts for the corresponding digital chips. FIG. 1 shows a circuit diagram of a typical buck converter. As shown in FIG. 1, the buck converter includes an input filter capacitor Cin, a main switching element Q1, an auxiliary switching element Q2, an inductor L and an output capacitor Co. The input filter capacitor Cin is electrically connected with a power source for receiving an input voltage Vin. The main switching element Q1 performs a turn-on and turn-off operation to adjust the output voltage Vo and the output current Io. The output current Io of the buck converter is provided to a load RL, i.e. the digital chip or a CUP.
For improving the properties of the power module, the current industry tends to optimize the semi-conductors and the inductors L significantly. Although both of them are optimized to a considerable degree, the optimization chance is getting smaller so that the further optimization is limited.
Therefore, there is a need of providing a new power module in order to overcome the above drawbacks encountered by the prior arts.